It is known to vacuum-form two-dimensional sheets to create three-dimensional formed films, by causing a softened or molten polymer sheet to conform to the shape of a forming screen. Commonly utilized apertured formed film topsheets are disclosed in, for example U.S. Pat. Nos. 3,929,135, 4,324,246, 4,342,314, 4,252,516, 4,535,020, 5,591,510, and U.S. patent application Ser. No. 10/082,040 filed Feb. 20, 2002. The formed films described in these publications are formed by application of a fluid pressure differential where the fluid preferably is air to thereby cause the polymer sheet to conform to the screen and also to cool. A preferred feature of these formed films is that the polymer crystallizes, or “sets” after the molten polymer has been formed. The resultant formed film therefore is said to have “memory.” Memory enables the formed film to regain its original form after non-deforming forces are applied to it, for example while the film is stored in the form of a wound roll. A disadvantage of vacuum formed films is that the body contacting surface of the film my have a plastic feeling that can feel both sticky and hot to the wearer of the article.
It also is known to utilize high pressure water jet systems, known as hydroforming systems, to cause two-dimensional polymeric films to conform to forming screens in order to create three-dimensional films. U.S. Pat. Nos. 4,609,518, 4,629,643, 4,695,422, 4,778,644, and 4,839,216, all to Curro (referred to herein as “Curro”) and assigned to Procter & Gamble, and U.S. Pat. Nos. 5,770,144, 6,022,607, and 6,240,817 assigned to McNeil, describe a multitude of film designs created by the combination of forming screens using high pressure water jet systems. In these systems, pressurized water is ejected from nozzles projecting water onto the surface of a polymeric film causing it to conform to the surface of an underlying support screen. The screen has indentations or perforations disposed on its surface. As the screen rotates it causes subsequent portions of the film to pass under the water jet causing subsequent portions of the film to conform to the screen. An advantage of this method of making formed films is that the number of protrusions that can be made in a specific surface area of film is greater than what is possible in a vacuum formed film process. Another advantage is that by utilizing water to deform crystalline film high levels of energy are applied to the film thereby causing more work and making the film softer. A disadvantage of known hydroformed films is that liquid jets apply forming energy unevenly across the film surface causing variation in the important film properties that limits the functionality of the film.
The description herein of certain advantages and disadvantages of known materials, and methods of their preparation, is not intended to limit the scope of the present invention. Indeed, the present invention may include some or all of the methods and materials described above without suffering from the same disadvantages.